PLANETARY PHENOMENA FOR SEPTEMBER, 1880. 287 
NS ROU IMIN, 
PLANETARY PHENOMENA FOR SEPTEMBER, 1880. 
BY W. W. ALEXANDER, KANSAS CITY. 
Mercury, during this month, is in an unfavorable position for observation, 
except in the beginning, when it may be seen before sunrise in the morning.. It 
rises on the rst at 4 hours and 18 minutes a. m., Kansas City mean time; sets on 
the 30th at 6 hours 4 minutes p. m., and is in superior conjunction with the sun 
on the 17th 3 hours a. m. 
Venus may be seen in the evening twilight during the entire month. It 
sets on the 1st at 7 hours and .o5 minutes p. m., 30th at 6 hours 33 minutes p. 
m. On the 7th it is in close conjunction with Mars, being only 31 minutes of arc 
north of that planet (or about the diameter of the moon). 
Mars being too near the sun and nearly at its maximum distance from the 
earth shows to a poor advantage. It sets on the 1st at 7 hours 11 minutes p.m., 
on the 30th at 6 hours oo minutes p. m., and is in close conjunction with Mer- 
cury on the 28th; distance 6 minutes of arc north. 
Jupiter, together with its four moons, forms a superb object for the telescope 
during this month, rising as follows: On the ist at 8 hours and 4 minutes p. m., 
on the 30th at 6 hours and 5 minutes p. m. 
The moons, as they course round the primary in their orbits, present some 
interesting phenomena, of which the following are the most important to be 
observed at Kansas City. On the evening of the 3d at 10 hours and 34 minutes, 
the 3d satellite may be seen to emerge from behind the body of Jupiter or re-ap- 
pear after occultation. 
On the 5th at 11 hours 27 minutes p. m. the 2d satellite may be seen to 
enter on the planets’ disk, preceded by its shadow, 1 hour and 36 minutes, both 
of which can be seen on the disk of the planet at the same time. 
On the 7th at oo hours 28 minutes 11 seconds a. m. the rst satellite will 
suddenly disappear by entering the shadow of Jupiter, and will reappear, coming 
from behind the planet at 3 hours 24 minutes a. m. 
The same occurs again on the 8th, the reappearance being at 9 hours and 50. 
minutes p. m. 
On the roth the 3d satellite enters the shadow of Jupiter and disappears at 
9 hours co minutes 32 seconds p. m., and reappears at 11 hours 28 minutes 51 
seconds p. m., and remains visible 23 minutes and disappears behind the planet’s. 
disk for more than two hours. 
On the 12th the 2d satellite again makes a transit together with its shadow 
